Quality improvement for RC06 chip resistor

This paper studies a quality improvement case of extremely thin and light chip resistor RC06. We use an L18(2¹ × 3⁷) orthogonal array allocating eight control factors in an experimental plan. The quality response data are inevitably considered to be ordered categorical. Six categories are classified for the quality of chips. Both Taguchi's accumulation analysis method (1966) and Nair's scoring scheme (1986) are employed in analysing the data. Furthermore, we develop a weighted probability scoring scheme (WPSS) and a signal‐to‐noise (SN) ratio to reach an optimal solution. Finally, a comparison among the three approaches is made.